云南高原楚雄市近50年气温、降水变化特征分析

Study on the Characteristics of Temperature and Precipitation Change in Chuxiong City on the Yunnan Plateau in Recent 50 Years

利用楚雄市1971~2020年的气温和降水数据,分析此时间段内楚雄市气温和降水的变化特征。结果显示:近50年楚雄市年平均气温呈现波动升高,从1987年开始上升趋势显著,近50年来夏季温度最高、冬季最低,最高温出现在6月(21.6℃),最低气温出现在1月(9.2℃),气温具有不同尺度的周期性震荡,第一主周期为30a时间尺度,经历了5个阶段的增减交替变化,2013~2020年的等值线没有闭合,预计未来几年的气温会持续上升。近50年降水量波动明显,呈下降趋势,年内降水主要集中于雨季(5~10月),干季(11至次年4月)降水少,楚雄市的降水量在7月份出现最大值(154.7 mm),在2月份出现最小降水量(8.1 mm),小波分析表明有32 a的主周期变化,主周期内降水量经历了5个阶段的增减交替变化,并且在2013~2020年阶段的等值线没有闭合,预测在未来几年内降水量还会增多,降水量在1983年发生突变;楚雄市气温和降水量年内分布不均匀,雨热不同期,最高气温出现在6月,而降水量峰值出现在7月,降水量最大值比气温最高值落后一个月。

Based on the data of temperature and precipitation in Chuxiong City from 1971 to 2020, the variation characteristics of temperature and precipitation in Chuxiong City during this period are analyzed.The results show that the annual average temperature in Chuxiong City has fluctuated and increased in recent50 years, with a significant upward trend since 1987. In recent 50 years, the temperature is the highest in summer and the lowest in winter. The highest temperature appears in June(21.6℃), and the lowest temperature appears in January(9.2℃). The temperature has periodic oscillation in different scales. The first main cycle is a 30a time scale, which has experienced five stages of alternating changes. The isoline from 2013 to 2020 is not closed, and the temperature is expected to continue to rise in the next few years;In the past 50 years, the precipitation fluctuated obviously and showed a downward trend, and the precipitation in the year mainly falls from May to October. In the dry season, from November to April, the precipitation in Chuxiong City was less.The maximum precipitation(154.7 mm) was registered in July and the minimum(8.1 mm) in February. Wavelet analysis has identified a main 32-year cycle in which the precipitation has experienced an alternating change of increase and decrease in five stages. Moreover, the isoline in 2013-2020 is not closed. So it is predicted that the precipitation will increase in the next few years, and the precipitation suddenly changed in1983;The temperature and precipitation in Chuxiong City are unevenly distributed throughout the year. In different periods of rain and heat, the highest temperature appears in June, while the highest precipitation appears in July, with maximum precipitation falling one month behind the maximum temperature.